Fix assertion on deleting and moving same item
Fix assertion message typo
Fix move operations when batched with deletes

Since deletes happen before moves, indexPathBeforeUpdate.item may no
longer point to correct index, so search for the object we're looking
for and use its index.
Add batch update example app
Merge pull request #295 from aburgel/move_fixes

Fix batch updates with NSFetchedResultsController assertions